1. Technical Field
The present invention relates in general to an improved data processing system and in particular to an improved method and system for generating high resolution graphics in a data processing system. Still more particularly, the present invention relates to a method and system for providing a simultaneous high resolution display within multiple virtual DOS applications in a data processing system.
2. Description of the Related Art
Computer display systems have become increasingly complex in recent years. This is particularly true with respect to the so-called "personal" computer. Since its initial introduction the personal computer has gradually enhanced the video graphic capability of such systems to permit personal computers to meet more sophisticated demands in the display area.
Initially, personal computers often utilized Color Graphics Adapters or CGA capable of a resolution of 640.times.200 pixels and up to four colors. These adapters were quickly supplanted by so-called "Enhanced Graphics Adapters" (EGA) capable of a resolution of 640.times.350 pixels while displaying up to sixteen colors, out of a possible list of sixty-four colors.
In recognition of a demand for improved video graphic capability within personal computers International Business Machines Corporation introduced the PS/2 personal computer in 1987 which adopted a new graphic standard. This standard is the Video Graphics Array (VGA) which was capable of a resolution of 640.times.480 pixels, while displaying up to 256 colors simultaneously out of a color palette of over 250,000 colors. Unlike the previous Enhanced Graphics Adapter (EGA), the new standard is able to both read and write hardware registers and was quickly adopted as the industry standard, providing a substantial improvement in the video display art. Numerous manufacturers have provided so-called "video adapter" boards which were capable of reproducing the Video Graphics Array (VGA) mode within existing computers.
More recently, this Video Graphics Array (VGA) mode has been surpassed by the so-called "Super Video Graphics Array" (SVGA) mode is capable of providing a resolution of 1,024.times.768 pixels and 256 colors. Numerous manufacturers now provide video adapters capable of supporting this highly enhanced video mode. For example, the Tseng Laboratories ET4000; ATI Technologies AT128800; Headland Technology HT209; Trident Microsystems TVGA8900; Western Digital Imaging WD90C1 1; Cirrus Logic CL-GD5422; and, the IBM VGA256C.
In order to utilize one of these SVGA graphics adapters it is necessary to provide an appropriate device driver which is capable of determining and setting the necessary registers within the data processing system which are required to implement these resolutions. This is typically accomplished in the prior art by statically coding the necessary information into the device driver.
While SGVA graphics adapters have provided an increase in the possible resolution of displays within personal computers, the manipulation of the large amount of data necessary to provide such resolutions has not been possible in the simultaneous display of multiple virtual DOS applications within a data processing system. High resolution graphics displays require the utilization of multiple banks of data within video buffers and the execution of multiple virtual DOS applications within so-called "Virtual DOS Machines" (VDM) has therefore not been implemented. Medium resolution displays which do not incorporate multi-bank video buffers have been implemented; however, the utilization of SGVA graphic adapters has led to a desire on the part of computer users to implement these high resolution graphic displays within all executing applications within a data processing system.
Thus, it should be apparent that a need exists for a virtual device driver which is capable of supporting the simultaneous high resolution display of graphics within multiple virtual DOS applications in a data processing system.